Aluminum nitride surface functionalized by polymer derived silicon oxycarbonitride ceramic for anti-hydrolysis

Abstract

Aluminum nitride (AlN) features an extremely interesting combination of very high thermal conductivity and excellent electrical insulation; therefore, it has been widely used in the high power electronic devices. The hydrolytic reaction of aluminum nitride powder decays the shelf-life and lowers the high power operating performance of the electronic devices. A protecting film of the polymer derived silicon oxycarbonitride ceramic is coated and fully wrapped on the surface of aluminum nitride powder against facilitating hydrolysis. Poly (organosilazane) precursor is incorporated with the commercial aluminum nitride powder pyrolyzed at 700 °C under argon environment for few hours to form a core-shell structure with a film thickness, 10–20 nm of silicon oxycarbonitride (SiCNO) ceramic shell and the aluminum nitride core. Measuring the pH value of SiCNO/AlN core-shell powder in deionized water at room temperature is to observe the hydrolytic behavior that its pH value is stable to maintain about 10 at ambient environment over ten days, whereas for the characterization of the reaction products, XRD, SEM and TEM analyses are employed. The hydrolytic behavior measured at 90 °C also shows that the SiCNO/AlN core-shell powder is still able to keep the protection from high temperature hydrolysis. XRD spectra proves that the characteristic crystalline peaks of SiCNO/AlN core-shell powder after hydrolysis over ten days are still the same as those of the commercial aluminum nitride powder before hydrolysis. These results directly indicate that the polymer derived silicon oxycarbonitride ceramic film fully protects the aluminum nitride powder from hydrolysis. When the content of silicon oxycarbonitride shell reduces to reach certain value, the hydrolytic protection gradually vanishes for long time.